Long-term clinical outcomes in elderly patients with chronic total occlusion and type 2 diabetes: the impact of coronary collateralization following successful recanalization

Abstract

Background and purpose: Chronic total occlusion (CTO) lesions commonly affect elderly patients, especially those with type 2 diabetes mellitus (T2DM), often associated with coronary collaterals (CC). However, it remains unclear whether CC influences the prognosis of CTO. This retrospective single-center study aimed to evaluate the prognostic relevance of CC in elderly patients with T2DM after successful revascularization for CTO. Methods: We analyzed data from 416 patients diagnosed with CTO who underwent successful revascularization between January 2013 and January 2017. Patients were categorized into two groups: the Non-T2DM group and T2DM group. Subgroup analyses were performed based on the status of CC. The primary outcome was the occurrence of major adverse cardiac events (MACE) during the follow-up period, with the secondary outcomes including all-cause mortality, cardiac death, and repeat revascularization. Results: CC did not significantly impact clinical endpoints in the overall elderly patient population. However, we observed a lower incidence of MACE, cardiac death, all-cause mortality, and repeat revascularization in the Non-T2DM group compared to the T2DM group. In patients without T2DM, poor-CC was associated with higher rates of all-cause mortality (9% vs. 18%, P = 0.041), an increased risk of cardiac death (5% vs. 12%, P = 0.042), and a greater incidence of MACE (15% vs. 28%, P = 0.031), whereas no such associations were observed in T2DM patients. Furthermore, in multivariate Cox analysis, T2DM emerged as an independent factor influencing the time to MACE (adjusted hazard ratio [HR]:1.847, 95% confidence interval [95% CI]: 1.215–2.810, P = 0.004) and repeat revascularization (adjusted HR: 2.093, 95% CI: 1.310–3.344, P = 0.002) in elderly CTO patients, rather than coronary collateralization. Notably, regardless of the quality of CC, elderly patients with T2DM exhibited a poorer prognosis. Conclusions: Elderly patients without T2DM derived greater long-term survival benefits from successful revascularization of CTO compared to those with T2DM. Additionally, good collateralization was associated with a decreased risk of adverse clinical outcomes specifically in Non-T2DM patients.